JPH0684440A - Thermoswitch - Google Patents

Abstract

PURPOSE:To provide a thermoswitch in which the opening of a contact is great as compared to the curving depth of a bimetal. CONSTITUTION:A pair of conductive terminal blocks 2, 3 are secured at intervals to a nonconductive base 1 and a conductive, movable plate 10 for switching both of the terminal blocks on and off is disposed between the terminal blocks 2, 3, and a bimetal 14 is disposed which takes the form of a Bellevile spring and is reversed depending on temperature so as to operate the movable plate 10. A locking protruding portion 13 located at one end of the bimetal 14 is fitted into the lock hole 15 of the terminal block 3 and is thereby locked in position and is directed toward the movable plate 10 with an opposite free end 11a serving as a point of application of force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoswitch which is used in an electric device having a heat source such as an electric rice cooker and which opens and closes an electric circuit according to the temperature of the electric device.

[0002]

2. Description of the Related Art As this type of thermoswitch, the one shown in FIG. 5 has been conventionally known. In this, a pair of conductive terminal plates 31 and 32 is fixed to a non-conductive substrate 30 with a gap, and one end is fixed to the first terminal plate 31 and the other end contact is provided between these terminal plates. 33a is the second terminal plate 3
Conductive movable plate 3 that can freely come into contact with and separate from the second contact portion 32a
3 is disposed, and the bottom surface of the movable plate 33 is inverted by heat to switch the movable plate 33.
As shown in FIG. 5, the bimetal 34 is curved so as to be convex upward and is separated from the movable plate 33, and the contact 33a of the movable plate 33 becomes the contact portion 32a of the second terminal plate 32. When the electric device or the like generates heat and reaches a predetermined temperature from the contacted ON position at room temperature, the heat causes the bimetal 34 to reverse to the state of FIG. 6 and push up the movable plate 33.
When the contact 33a is separated from the second terminal plate 32 to open the electric circuit and the temperature is lowered, the bimetal 34 is removed again.
The state is reversed and restored to close the contact 33a.

However, in the above-mentioned conventional thermoswitch, the bimetal 34 is supported on the substrate 30 with the center point serving as a fulcrum, and both free ends 34a, 34 at the time of reversal by heat.
Since the movable plate 33 is pushed up by a, there is a disadvantage that the opening h of the contact 33a cannot be made sufficiently large. That is, the opening h of the contact 33a is the bending depth d when the bimetal 34 is reversed (see FIG. 7).
Therefore, in order to make the opening degree h large enough, it is necessary to make the bending depth d large enough to be commensurate with it. However, the bending depth d is made too large due to restrictions such as molding conditions of the bimetal 34 and operating characteristics. Therefore, the opening h of the contact 33a cannot be set too large.

Also, in connection with the small opening of the contact,
There is also a drawback that a so-called chattering phenomenon in which the contact flutters when opened is likely to occur. Therefore, in the past, by adjusting the gap between the bimetal and the movable plate at room temperature as small as possible, the contact opening can be maximized by making the most effective use of the displacement of the free end when the bimetal is reversed. I tried to take it, but it was a fraction of a meter
The adjustment work was very troublesome because the gap had to be adjusted at two positions at both ends of the bimetal in addition to the adjustment at a minute distance of m.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoswitch in which the contact opening is larger than the bending depth of the bimetal and the gap can be easily adjusted to prevent chattering. .

[0006]

In order to solve the above-mentioned problems, according to the present invention, a pair of conductive terminal plates are fixed to a non-conductive substrate at intervals, and both ends of the terminal plates are fixed between the terminal plates. A disc spring type bimetal is provided which is provided with a conductive movable plate which can be switched between an on position for conducting the slave plate and an off position for disconnecting it from the non-conductive state, and which switches the movable plate by reversing according to temperature. In the thermoswitch with, lock one end of the bimetal in place,
It is characterized in that the free end on the opposite side is made to face the movable plate as a point of action of force.

It is also possible to provide a guide at a position closer to the locking portion side than the center portion of the bimetal and to guide the transition when the bimetal is reversed by the guide.

[0008]

The bimetal is bent in a direction away from the movable plate, and when the temperature of the electric device or the like rises to a predetermined temperature from the state where the movable plate is in the ON position at room temperature, the bimetal is inverted by the heat. , Switch the movable plate to the off position where the contacts open. And when the temperature of electrical equipment etc. drops,
The bimetal reverses in the opposite direction and returns to move away from the movable plate, and the movable plate is switched to the ON position where the contacts are closed.

When the bimetal is inverted by heat, one end of the bimetal is locked at a fixed position, and the free end on the opposite side is lifted with the locking part as a fulcrum to push the movable plate. Becomes large according to the distance between the fulcrum and the free end, and as a result, the contact opening becomes very large.

Further, since the opening of the contact is large as described above, chattering is unlikely to occur, and the amount of displacement of the free end of the bimetal is large, so that the free end of the bimetal and the movable plate at room temperature are large. The gap can be made large, and as a result, it is not necessary to finely adjust the gap to prevent chattering, and it is only necessary to adjust the gap at one end of the bimetal, which makes the adjustment work very easy. .

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIGS. 1 and 2, reference numeral 1 denotes a substrate made of a non-conductive material such as alumina or synthetic resin. A pair of conductive first and second terminal plates 2 and 3 is fixed to both ends of the terminal 1 with a space.

The first terminal board 2 contacts the lower surface of the substrate 1,
It is fixed to the substrate 1 by a fixing member 5 penetrating the substrate 1 and protruding to the upper surface, and the first terminal plate 2 is attached to the upper end of the fixing member 5.
A contact point 2a is formed which communicates with. Further, the second terminal plate 3 has its end portion bent into a key shape and abuts against the side surface and the upper surface of the substrate 1, and is fixed to the substrate 1 by the caulking portion 7 that holds the substrate 1 from both sides. A terminal portion 3a extending in the axial direction of the terminal plate 3 is formed by cutting and raising a part of the terminal plate 3 at a base end portion 3b of the second terminal plate 3 which is in contact with the upper surface of the substrate. At the same time, the guide projection 8 that rises upward is formed by cutting and raising a part of the base end portion 3b.

A conductive movable plate 10 is provided between the two terminal plates 2 and 3 to connect the terminal plates 2 and 3 to a conductive state or to disconnect the terminal plates from a non-conductive state. The movable plate 10
Has one end fixed to the terminal portion 3a of the second terminal plate 3, and the contact 10a formed at the other end is the contact 2a of the first terminal plate 2.
The contact point 10a normally occupies the closed ON position (see FIG. 1) by the elastic force of the movable plate itself.

On the lower surface of the movable plate 10, there is provided a disc spring-shaped bimetal 11 which is turned upside down depending on temperature to switch the movable plate 10. As shown in FIG. 3, the bimetal 11 has a locking projection 13 at one end and a guide hole 14 at a position closer to the locking projection 13 side than the central portion. Then, the locking projection 13
Is a locking hole 1 formed in the terminal portion 3a of the second terminal plate 3.
5 is fitted and locked, and the guide projection 8 is fitted in the guide hole 14 to be disposed on the base end portion 3b of the second terminal plate 3 and the locking projection 13 is provided. The free end 11a on the opposite side of the movable plate 1 serves as a point of action of force.
It faces the lower surface of 0. In this case, at the position where the free end 11a of the lower surface of the movable plate 10 abuts, the abutting protrusion 10b is provided.
Is desirable to be formed.

The thermoswitch having the above structure is used, for example, in an electric rice cooker. When the temperature of the electric rice cooker is lower than a predetermined temperature, the bimetal 11 has a convex shape as shown in FIG. Since the free end 11a is curved and is separated from the movable plate 10, the movable plate 10 occupies the ON position where the contact 10a is closed.

When the electric rice cooker heats up from this state and the temperature rises to a predetermined temperature, the heat causes the bimetal 11 to invert into a downward convex shape as shown in FIG. Since the movable plate 10 is switched to the off position where the contact 10a is opened, the electric circuit is opened. in this case,
In the bimetal 11, the locking projection 13 provided at one end is locked in the locking hole 15, and the free end 11a on the opposite side is reversed by reversing the end on the locking projection 13 side as a fulcrum. Is lifted and pushes up the movable plate 10, the free end 11
The displacement amount of a becomes large according to the distance between the fulcrum and the free end 11a, whereby the opening h of the contact 10a can be made sufficiently large. When the temperature of the electric rice cooker is lowered, the bimetal 11 is again reversed to the state of FIG. 1 and returned to separate from the movable plate 10, so that the movable plate 10 contacts the contact 1
0a switches to the closed on position.

Since the opening of the contact 10a is large as described above, chattering is unlikely to occur, and the amount of displacement of the free end of the bimetal 11 is large. Therefore, the free end of the bimetal 11 and the movable plate 10 at room temperature. It is possible to make a large gap between and, and as a result, it is not necessary to finely adjust the gap to prevent chattering, and it is sufficient to adjust the gap only at one end of the bimetal 11. It's very easy.

The guide 8 is used to guide the bimetal 11 when it is positioned and inverted.

[0019]

As described in detail above, according to the thermoswitch of the present invention, one end of the bimetal is locked at a fixed position to serve as a fulcrum for reversing, and the free end on the opposite side is movable as a force acting point. Since it faces the plate, the amount of displacement at the free end can be increased regardless of the bending depth of the bimetal, and thus the opening of the contact can be made sufficiently large.

Further, by increasing the opening of the contact as described above, the occurrence of chattering can be surely prevented, and since the amount of displacement of the free end of the bimetal is large, the free end of the bimetal at room temperature is large. The gap between the movable plate and the movable plate can be large, and as a result, it is not necessary to finely adjust the gap to prevent chattering, and the gap can be adjusted only at one end of the bimetal. The work becomes very easy.

[Brief description of drawings]

FIG. 1 is a sectional view of a thermoswitch of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a plan view of a bimetal.

FIG. 4 is a cross-sectional view of the thermoswitch of FIG. 1 in different switching states.

FIG. 5 is a cross-sectional view of a conventional example.

6 is a cross-sectional view of the different switching states of FIG.

FIG. 6 is a sectional view of a bimetal.

[Explanation of reference numerals] 1 substrate 2, 3 terminal plate 10 movable plate 11 bimetal

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 14, 1991

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure amendment]

[Submission date] August 3, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thermoswitch of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a plan view of a bimetal.

4 is a cross-sectional view of the thermoswitch of FIG. 1 in different switching states.

FIG. 5 is a sectional view of a conventional example.

6 is a cross-sectional view of the different switching states of FIG.

FIG. 7 is a sectional view of a bimetal.

[Explanation of reference numerals] 1 substrate 2, 3 terminal plate 10 movable plate 11 bimetal

Claims (2)

[Claims] 1. A pair of electrically conductive terminal plates are fixed to a non-conductive substrate at intervals, and between these terminal plates,
In addition to disposing a conductive movable plate that can be switched between an ON position for conducting both terminal plates and an OFF position for disconnecting them in a non-conducting state, a disc spring type that reverses according to temperature and switches the movable plates. A thermoswitch provided with a bimetal, wherein one end of the bimetal is locked at a fixed position and the free end on the opposite side is made to face a movable plate as a point of action of force. 2. The thermoswitch according to claim 1, wherein the bimetal is guided by a guide at a position closer to the locking portion side than the center portion of the bimetal, when the bimetal is reversed.